Emission Spectroscopy of the Cathode Fall Region of an Analytical Glow Discharge

Abstract

Stark spectroscopy of hydrogen Balmer lines and neutrai helium lines with forbidden components is used for the study of an analyticai glow discharge. Splitting of the hydrogen Hβ and Hγ lines is applied for simultaneous determination of local electric field and temperature of excited H atoms in pure hydrogen and in argon-hydrogen mixture. Temperature measurements showed that, in pure hydrogen discharge, at least two groups of excited atoms exist : "slow", with average energies in the range from 3.4 eV to 8.2 eV and "fast", ranging between 80 eV and 190 eV. In argon-hydrogen discharge, excited hydrogen neutrals with average energies between 32 eV and 43 eV are detected only. The origin of these energetic neutrals is related to the presence of H+ and H3+ : ions in pure hydrogen, and to the dominant role of H3+ ion in argon-hydrogen mixture. For both gases, in the negative glow region, the increase of the exited hydrogen atoms temperature is detected and explanation suggested. For the electric field measurements in pure helium and helium-hydrogen mixture, the Stark splitting and shitiig of the neutral helium 492.19 nm, 447.15 nm and 406.62 nm with respect to their forbidden counterparts is used. Good agreement between electric field measurements from these three helium lies is obtained

The Space-Time Distribution of Electrical and Optical Characteristics of High-Voltage Pulsed Discharge Plasma in Helium

“…Heavy lines on the right and left indicate the positions of the radiation intensity peaks for the forbidden 4F-2Р-and allowed 4D-2Р-components of He-atom radiation, lying in the electrode gap. The calculation of E(t) for the above-mentioned values of х was performed by measuring the distance δλ(t) between the spectral peaks of the 4F-and 4D-2Р-components using the procedure reported in [3]. Figure 2 shows the calculated values of E(x) for the time points t 1 = 0.175, t 2 = 0.245, t 3 = 0.42 and t 4 = 0.595 μs.…”

Doppler spectroscopy of hydrogen Balmer lines in a hollow cathode water vapour and argon–water vapour glow discharge

“…For the studies of this phenomenon, apart from various types of HCGD, other low-pressure electric discharges were used as well, see . Fast excited hydrogen atoms moving towards and from the cathode are also detected in a plane parallel electrode GD [6], Townsend discharge with plane parallel electrodes [7], plane cathode-hollow anode GD with different cathode materials in hydrogen and in hydrogen containing gas mixtures [8,9,12,16,17,22,24]. The discharges were dc [2, 3, 5-9, 11-13, 16-18, 20-25, 27, 29] or rf [4, 10, 14, 15, 19-21, 26, 28] excited.…”

Study of fundamental processes affecting the structure of the cathode zone of nitrogen/titanium dc discharge

“…The fast heavy particles-cathode interaction in dc glow discharges, important from a practical point of view, is affected by the phenomena occurring in the cathode sheath plasma, for example these phenomena influence species-energy-angle distributions of bombarding particles. Even particular discharge characteristics, such as the lighting of the cathode region plasma, have yet not been explained, see [1][2][3]. The electron-molecule excitation and the Penning effect are assumed to be the main processes producing plasma lighting in the negative glow, see Broekaert in [4].…”